I have a 8.1.5 database amd want to take full database export,
I also want the data, but not the actual values, e.g.
if there is a name column amd the name is mike, then I, want a randomly assigned name for it.
but the problem will be when it will be primary key or have some constraint on it, also i want it for complete database at a time, is there any procedure or method or such a thing.
thank you.

It is not an Oracle issue but an application one.
Only the application knows what are the relation between the values, what are the consistency rules, how to obfuscate them and which ones to obfuscate...